CLASSIFICATION OF APUS
PHYLUM :- ARTHROPODA (Jointed appendages.)
CLASS :- CRUSTACEA (Thick exoskeleton, antennae 2 pairs)
SUB-CLASS :- BRANCHIOPODA (Trunk appendages act as gills)
ORDER :- NOTOSTRACA (Carapace present)
GENUS :- Apus (Tadpole shrimp)
It is found in most parts of the world especially in U.S.A., Kansas, Lower California, Texas, Mexico and Nebraska.
HABIT AND HABITAT
Apus is a fresh-water form.
GENERAL CHARACTERSTICS OF APUS
- Commonly called as Tadpole shrimp.
- Body divisible into head-thorax (Cephalothorax) and abdomen measuring 20 to 30 mm in length.
- Head is broad, depressed and covered by a horse-shoe shaped carapace which bears eyes above, antennules and antennae beneath. The labrum, mouth, antennules, antennae, mandibles, maxillae are present ventrally.
- Anterior two-thirds of the dorsal surface is covered by a thin chitinous shell or carapace, which covers major part of the body.
- Beyond the posterior edge of the carapace a cylindrical and segmented abdomen projects.
- Last segment bears anus and a pair of long caudal styles.
- On the dorsal surface of the carapace, near its anterior border, are paired eyes, median eye and dorsal organ
- Sexes are separate. Males are few. In females few segments are without swimming
- Development includes nauplius larva.
Reproduction is as a rule parthenogenetic because the males are rare. How they are able to carry genetic continuity is not clear.
The animal contains horse-shoe shaped carapace and all above features hence it is Apus.